A nano-carbon reinforced ultra-fine cement-based blocking material and a preparation method and application thereof

Abstract

The application belongs to the technical field of geotechnical engineering, and particularly relates to a nano-carbon enhanced ultra-fine cement-based blocking material and a preparation method and application thereof. The prepared ultra-fine cement-based blocking material is prepared by uniformly mixing cement 45-50 parts, solid waste sintered active material 0.5-2.5 parts, water reducing agent 0-0.05 parts, carbon nanotube 0.015-0.1 parts, carbon quantum dot 1% solution 0.5-2.5 parts and water 45-50 parts. The material has low porosity and is not dispersed. The material has strong injectability and can penetrate into small pores. The material has high strength, high bonding and reinforcing strength for broken rock, and has wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geotechnical engineering, and particularly relates to a nano-carbon enhanced ultra-fine cement-based blocking material and a preparation method and application thereof. BACKGROUND

[0002] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be taken as an acknowledgement or any form of suggestion that this information forms prior art that is publicly known.

[0003] With the deepening of the development of mineral resources, especially after the mine gushing water accident, a large number of micro cracks are often formed in the rock stratum. These micro cracks not only weaken the structural stability of the rock stratum, but also provide a convenient channel for the infiltration of underground water, leading to the diffusion of pollutants in the mining area through these cracks, and further polluting the groundwater resources. Such pollution not only threatens the ecological environment of the mining area, but also poses a potential threat to the safety of the surrounding residents' domestic water.

[0004] At present, for the crack plugging after the mine gushing water accident, the commonly used grouting materials are mostly based on traditional materials such as cement, chemical slurry or polymer. However, due to the reasons such as large particle size or poor fluidity, these materials are difficult to effectively penetrate into the micro cracks, resulting in unsatisfactory plugging effect. This limitation makes it impossible to effectively control the underground water flow channel, and the pollutants can still continue to diffuse through the unsealed cracks, thereby exacerbating the environmental pollution problem.

[0005] In order to cope with this challenge, the technical personnel in the field urgently need to develop a new material that can penetrate and effectively seal the micro cracks. SUMMARY

[0006] In view of the problems existing in the prior art, the present application provides a nano-carbon enhanced ultra-fine cement-based blocking material and a preparation method and application thereof. The material prepared by the present application has low porosity and strong dispersibility, can penetrate into the micro pores, and can ensure that the material has high strength and high rock fragmentation and bonding reinforcement strength.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0008] In a first aspect, the present application provides a nano-carbon enhanced ultra-fine cement-based blocking material, the raw material composition of which includes, by weight: cement 45-50 parts, solid waste sintered active material 0.5-2.5 parts, water reducing agent 0-0.05 parts, carbon nanotube 0.015-0.1 parts, carbon quantum dot 1% solution 0.5-2.5 parts, and water 45-50 parts.

[0009] Preferably, the raw material composition of the ultra-fine cement-based blocking material includes cement 49 parts by weight, solid waste sintered active material 1.0 parts by weight, water reducing agent 0.05 parts by weight, carbon nanotube 0.1 parts by weight, carbon quantum dot 1% solution 0.5 parts by weight, and water 49.5 parts by weight.

[0010] Preferably, the cement adopts K700 (grade II) ultra-fine cement, and the fineness D90 is 18.3 μm.

[0011] Preferably, the solid waste sintered active material is selected from one or more of construction waste containing sulphoaluminate cement, coal gangue, fly ash, and by-products of sulphoaluminate cement production; further preferably, the construction waste containing sulphoaluminate cement is calcined solid waste sulphoaluminate treated by ultra-fine grinding technology and air classification technology.

[0012] Preferably, the carbon nanotube is selected from one or more of single-walled carbon nanotube, multi-walled carbon nanotube, double-walled carbon nanotube, open carbon nanotube, and closed carbon nanotube.

[0013] Preferably, the carbon quantum dot 1% solution is prepared with a weight ratio of solid carbon quantum dot (CQD) to water of 1:100.

[0014] In a second aspect of the present application, a preparation method of the above-mentioned nano-carbon enhanced ultra-fine cement-based blocking material is provided, comprising the following steps:

[0015] S1, mixing cement, solid waste sintered active material, and water reducing agent to obtain a powder component;

[0016] S2, mixing carbon nanotube, carbon quantum dot 1% solution, and water to obtain a liquid component;

[0017] S3, mixing the powder component and the liquid component to obtain the ultra-fine cement-based blocking material.

[0018] Preferably, in step S1, the weight ratio of the cement, solid waste sintered active material, and water reducing agent is 45-50:0.5-2.5:0-0.05; and the water reducing agent is polycarboxylic acid high-efficiency water reducing agent powder.

[0019] Preferably, in step S2, the weight ratio of the carbon nanotube, carbon quantum dot 1% solution, and water is 0.015-0.1:0.5-2.5:45-50.

[0020] Preferably, in step S2, the carbon nanotube is fully dispersed in the mixed solution before mixing the powder component.

[0021] In a third aspect of the present application, the nano-carbon enhanced ultra-fine cement-based blocking material of the first aspect is provided for use in the control and prevention of mine groundwater pollution.

[0022] The beneficial effects achieved by one or more technical solutions of the present application are as follows:

[0023] (1) The ultra-fine high-efficiency cement-based blocking material prepared by the present application significantly improves the permeability of the material by optimizing the particle size through ultra-fine grinding technology, and can effectively penetrate into the micro-fissure and pore medium of the mining area. The material can quickly seal the small underground water channel and prevent the spread of pollutants with water flow, and is particularly suitable for emergency treatment after sudden gushing accidents in mining areas.

[0024] Among them, the ultra-fine grinding and air classification treatment optimize the uniformity and distribution of particles, making the particle size more concentrated, so that it can penetrate into smaller pores and cracks, and improve the injectability of the grouting material. Smaller particle size can more easily fill the micropores in the material, reduce the overall porosity, and enhance the density of the material. Air classification removes larger particles, reduces friction and obstruction between particles, reduces the viscosity of the slurry, and improves the fluidity of the slurry.

[0025] (2) The present application uses high-efficiency solid waste sintered active material, so that the material can quickly set and obtain high early strength after grouting, effectively forming a stable sealing barrier to prevent groundwater seepage. The high early strength performance of the material ensures that the sealing operation is completed in a short time, and the spread of groundwater pollution is prevented to the greatest extent.

[0026] (3) The present application utilizes the pozzolanic effect and microcosmic cementitious hydration mechanism, and the durability and impermeability of the material are greatly improved after solidification. Through the active reaction of the pozzolanic material, the internal structure of the material is more dense, which enhances its crack resistance and water erosion resistance, ensuring the long-term stability of the material in complex underground environment.

[0027] (4) The present application uses ultra-fine solid waste sintered active material as a reinforcing component, not only effectively improves the physical and mechanical properties of the material, but also realizes the resource utilization of solid waste, reduces the cost of the material, and meets the requirements of sustainable development.

[0028] (5) The present application introduces self-developed multi-functional carbon quantum dots modified carbon nanotubes as a surface reinforcing agent. In unmodified CNTs, strong van der Waals forces cause carbon nanotubes to aggregate into bundles, making it difficult to disperse in liquid media or matrix. CQDs physically adsorb by stacking with the surface π-π bond of CNTs, shielding the van der Waals forces between the tubes and preventing them from intertwining or aggregating. These multi-functional reinforcing agents not only improve the dispersibility of the material, but also improve the early strength and adhesion performance of the material through synergistic action with the matrix, while further enhancing the impermeability and overall durability of the material. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings constituting a part of the present application are used to provide further understanding of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application.

[0030] Figure 1 A physical map of the grouting material stone body prepared for the embodiment 1 of the present application;

[0031] Figure 2 A particle size distribution comparison chart before and after superfine grinding and air classification technology treatment of the superfine cement and solid waste sintered active material used in the embodiment of the present application;

[0032] Figure 3 A compressive strength test comparison chart of the superfine cement-based blocking material prepared in the embodiment and the comparative example of the present application;

[0033] Figure 4 A rheological property test comparison chart of the superfine cement-based blocking material prepared in the embodiment and the comparative example of the present application. DETAILED DESCRIPTION

[0034] It should be pointed out that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0035] In view of the increasingly serious problem of groundwater pollution caused by micro-fracture seepage in the mining area, and the complex micro-fracture and pore structure of the rock stratum in the mining area, water flow is difficult to effectively block, and conventional materials are difficult to meet the requirements of long-term water blocking and plugging effect. Therefore, the present application provides a superfine cement-based blocking material and a preparation method and application thereof. The material prepared by the present application can effectively fill the micro-fracture and form a continuous and dense water blocking barrier through the penetration capacity of superfine particles and high early strength characteristics, prevent the further spread of contaminated water, and ensure the safety and stability of the groundwater system.

[0036] In a first typical embodiment of the present application, a nano-carbon reinforced superfine cement-based blocking material is provided, and the raw material composition thereof includes, by weight: cement 45-50 parts, solid waste sintered active material 0.5-2.5 parts, water reducing agent 0-0.05 parts, carbon nanotube 0.015-0.1 parts, carbon quantum dot 1% solution 0.5-2.5 parts, and water 45-50 parts.

[0037] In one or more embodiments of the present application, the raw material composition of the superfine cement-based blocking material includes: solid waste sintered active material 1.0 parts, water reducing agent 0.05 parts, carbon nanotube 0.1 parts, carbon quantum dot 1% solution 0.5 parts, and water 49.5 parts.

[0038] In one or more embodiments of the embodiment, the cement adopts K700 (II grade) superfine cement, and the fineness D90 is 18.3 microns, and the execution standards are Q / K0001-2015 and GB / T35161-2017.

[0039] In one or more embodiments of the embodiment, the solid waste sintered active material is selected from one or more of the following: building waste containing sulphoaluminate cement, coal gangue, fly ash, and by-products of sulphoaluminate cement production; further preferably, the building waste containing sulphoaluminate cement is calcined solid waste sulphoaluminate cement treated by superfine grinding technology and air classification technology.

[0040] In one or more embodiments of the embodiment, the carbon nanotubes are selected from one or more of the following: single-walled carbon nanotubes, multi-walled carbon nanotubes, double-walled carbon nanotubes, open carbon nanotubes, and closed carbon nanotubes.

[0041] In one or more embodiments of the embodiment, the carbon quantum dot 1% solution is prepared with a solid carbon quantum dot (CQD) to water volume ratio of 1:100.

[0042] A second typical embodiment of the present application provides a preparation method of the above-mentioned nano-carbon enhanced superfine cement-based blocking material, comprising the following steps:

[0043] S1, mixing cement, solid waste sintered active material, and water reducing agent to obtain a powder component;

[0044] S2, mixing carbon nanotubes, carbon quantum dot 1% solution, and water to obtain a liquid component;

[0045] S3, mixing the powder component and the liquid component to obtain the superfine cement-based blocking material.

[0046] In one or more embodiments of the embodiment, in step S1, the weight ratio of the cement, the solid waste sintered active material, and the water reducing agent is 45-50:0.5-2.5:0-0.05; and the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent powder.

[0047] In one or more embodiments of the embodiment, in step S2, the weight ratio of the carbon nanotubes, the carbon quantum dot 1% solution, and the water is 0.015-0.1:0.5-2.5:45-50.

[0048] In one or more embodiments of the embodiment, in step S2, after the carbon nanotubes are fully dispersed in the mixed solution, the powder component is mixed.

[0049] A third typical embodiment of the present application provides an application of the above-mentioned nano-carbon enhanced superfine cement-based blocking material in the control and prevention of mine groundwater pollution.

[0050] The application will be described in further detail below with reference to specific embodiments, which are intended to explain the application but not to limit it.

[0051] Embodiment 1: The embodiment provides a nano-carbon reinforced ultra-fine cement-based blocking material and a preparation method thereof, including the following steps:

[0052] Step one: take the powder components by mass fraction, including the following components: 49 parts of finely ground ultra-fine cement, 1 part of solid waste sintered active material, and 0.05 parts of water reducing agent;

[0053] Step two: configure the liquid components by mass fraction, including 0.5 parts of 1% carbon quantum dot solution, 0.1 parts of carbon nanotube, and 49.5 parts of water;

[0054] Step three: sequentially and fully stir the above-mentioned raw materials according to the preparation method of the composite material;

[0055] Step four: remove part of the stirred material for liquidity test and rheological property test, pour the remaining material into a mold, and place it in a 20℃ environment for curing for 28 days.

[0056] Step five: test the compressive strength and porosity of the cured test block.

[0057] Embodiment 2: The embodiment provides a nano-carbon reinforced ultra-fine cement-based blocking material and a preparation method thereof, including the following steps:

[0058] Step one: take the powder components by mass fraction, including the following components: 50 parts of finely ground ultra-fine cement, 0.5 parts of solid waste sintered active material, and 0.05 parts of water reducing agent.

[0059] Step two: configure the liquid components by mass fraction, including 1.5 parts of 1% carbon quantum dot solution, 0.015 parts of carbon nanotube, and 48.5 parts of water.

[0060] Step three: sequentially and fully stir the above-mentioned raw materials according to the preparation method of the composite material.

[0061] Step four: remove part of the stirred material for liquidity test and rheological property test, pour the remaining material into a mold, and place it in a 20℃ environment for curing for 28 days.

[0062] Step five: test the compressive strength and porosity of the cured test block.

[0063] Embodiment 3: The embodiment provides a nano-carbon reinforced ultra-fine cement-based blocking material and a preparation method thereof, including the following steps:

[0064] Step one: take the powder components by mass parts, including the following components: 48 parts of finely ground ultra-fine cement, 1.5 parts of solid waste sintered active material, 0.05 parts of water reducing agent.

[0065] Step two: configure the liquid components by mass parts, including 1.5 parts of 1% carbon quantum dot solution, 0.015 parts of carbon nanotube, and 48.5 parts of water.

[0066] Step three: the above-mentioned raw materials are sequentially and fully stirred according to the preparation method of the composite material.

[0067] Step four: the removed part of the stirred material is tested for fluidity and rheological properties, and the remaining material is poured into a mold and cured at 20°C for 28 days.

[0068] Step five: the test block obtained by curing is tested for compressive strength and porosity.

[0069] Example 4: This example provides a nano-carbon reinforced ultra-fine cement-based blocking material and a preparation method thereof, including the following steps:

[0070] Step one: take the powder components by mass parts, including the following components: 46 parts of finely ground ultra-fine cement, 2 parts of solid waste sintered active material, and 0.05 parts of water reducing agent.

[0071] Step two: configure the liquid components by mass parts, including 2.5 parts of 1% carbon quantum dot solution, 0.015 parts of carbon nanotube, and 45.5 parts of water.

[0072] Step three: the above-mentioned raw materials are sequentially and fully stirred according to the preparation method of the composite material.

[0073] Step four: the removed part of the stirred material is tested for fluidity and rheological properties, and the remaining material is poured into a mold and cured at 20°C for 28 days.

[0074] Step five: the test block obtained by curing is tested for compressive strength and porosity.

[0075] Example 5: This example provides a nano-carbon reinforced ultra-fine cement-based blocking material and a preparation method thereof, including the following steps:

[0076] Step one: take the powder components by mass parts, including the following components: 47 parts of finely ground ultra-fine cement, 2.5 parts of solid waste sintered active material, and 0.05 parts of water reducing agent.

[0077] Step two: configure the liquid components by mass parts, including 2.5 parts of 1% carbon quantum dot solution, 0.035 parts of carbon nanotube, and 47 parts of water.

[0078] Step three: the above-mentioned raw materials are sequentially stirred according to the preparation method of the composite material.

[0079] Step four: the removed part of the stirred material is subjected to flowability test and rheological property test, and the remaining material is poured into a mold and cured at 20°C for 28 days.

[0080] Step five: the test block obtained by curing is subjected to compressive strength and porosity test.

[0081] Comparative Example 1: Different from the components of Example 1, the cement type in Step one is Hailuo 425 ordinary portland cement (ordinary cement), the fineness D90 is 75.6 μm, and the other components are the same as those of Example 1; the preparation steps are consistent with those of Example 1.

[0082] Comparative Example 2: Different from the components of Example 1, no solid waste sintered active material is added in Step one, and the other components are the same as those of Example 1; the preparation steps are consistent with those of Example 1.

[0083] Comparative Example 3: Different from the components of Example 1, the solid waste sintered active material in Step one is not treated by superfine grinding technology and air classification technology (ordinary inorganic early strength agent), and the other components are the same as those of Example 1; the preparation steps are consistent with those of Example 1.

[0084] Comparative Example 4: Different from the components of Example 1, the dispersant type in Step two is carbon nanotube PMA dispersion liquid, and the other components are the same as those of Example 1; the preparation steps are consistent with those of Example 1.

[0085] Comparative Example 5: Different from the components of Example 1, the addition amounts of carbon quantum dots and carbon nanotubes in Step two are 2.5 parts and 0.2 parts, respectively, and the other components are the same as those of Example 1; the preparation steps are consistent with those of Example 1.

[0086] Comparative Example 6: Different from the components of Example 1, no carbon quantum dot dispersant is added in Step two, and the other components are the same as those of Example 1; the preparation steps are consistent with those of Example 1.

[0087] Test Example 1: This test example is the flowability, porosity, compressive strength test and cost calculation of the ultra-fine cement-based blocking material prepared in the examples and comparative examples, as shown in Table 1 and Figure 3

[0088] Table 1

[0089]

[0090] From the data in Table 1, it can be seen that:

[0091] Comparing with Comparative Example 1, it can be seen that the fineness of ordinary cement is too high (such as Figure 2 ​As shown in the figure) lead to grouting material can not penetrate into the tiny cracks, easy to form a large block of particles in the slurry, increase the shear resistance, leading to an increase in viscosity, difficult to meet the performance requirements;

[0092] As can be seen from Comparative Example 2, not participating in the solid waste sintering active material or low dosage will lead to the anti-permeation performance of the blocking material to be reduced, and it is difficult to meet the performance requirements; and without adding inorganic early strength agent (solid waste sintering active material), the synergistic mechanism between the organic early strength agent (carbon nanotube) cannot be played, leading to continuous increase of the viscosity of the material;

[0093] As can be seen from Comparative Example 1 and Comparative Example 3, the treatment effect of superfine grinding and air classification on cement and early strength agent greatly optimizes the particle size distribution, reduces the overall particle size, and thus can improve the fluidity of the slurry and reduce the overall porosity (such as Figure 2 As shown in the figure); based on this, the present application adds early strength agent and the like to improve the overall performance of the material;

[0094] As can be seen from Comparative Examples 4-5, on the basis of meeting the basic performance, too much dosage of carbon nanotubes and carbon quantum dots leads to an increase in cost, and easy agglomeration, affecting the overall performance;

[0095] As can be seen from Comparative Example 6, without the addition of carbon quantum dot dispersant, in the unmodified CNTs, due to the large specific surface area and strong van der Waals force of the carbon nanotubes, the particles are easily attracted to each other and agglomerated to form larger lumps, which increase the shear resistance in the slurry, increase the viscosity of the slurry, and significantly reduce the fluidity of the material.

[0096] Therefore, the weight parts of cement and early strength agent (solid waste sintering active material, carbon nanotube) need to be controlled within this range, which can ensure that the grouting material has high strength and high injectability, and at the same time, will not cause an increase in cost.

[0097] As shown in the figure Figure 4 The viscosity time-varying curve is a curve reflecting the change rule of the viscosity of the material with time, which is used to analyze the evolution of the viscosity of the material with time under the action of static or shear stress. Under normal circumstances, the addition of early strength agent will accelerate the hydration reaction, and in this process, the internal structure of the material changes rapidly, leading to rapid increase of the viscosity and decrease of the fluidity, and the solidification structure is formed faster. In Examples 1-5, with the addition of appropriate weight parts of inorganic early strength agent and organic early strength agent, the viscosity of the material only shows a small increase at the initial stage of the reaction, and then the viscosity of the material remains stable with time, indicating that the fluidity of the material under stress conditions is relatively constant, and the injectability is good.

[0098] Application Example 1:

[0099] Grouting reinforcement tests are conducted in a laboratory environment to simulate the actual reinforcement process, allowing for the study and verification of grouting material performance, reinforcement effectiveness, and technical parameters. This process can help optimize actual construction plans and ensure the success of reinforcement work.

[0100] After adding coarse / fine aggregates into the cylindrical acrylic pipe, the pipe openings at both ends were sealed with water-permeable stones, and the grouting fixing device was placed inside. CNTs were dispersed in the CQDs solution in a plastic beaker, and after ultrasonic treatment for 5 min, they were added to the stirring pot. Superfine cement, solid waste early strength agent, and water reducing agent were added in sequence, and after fully stirring for 2 min according to the stirring procedure, the acrylic pipe was injected into the interior using a manual pressure pump with a pressure of 1.5 MPa.

[0101] According to the test report, the 28d compressive strength of the grouting reinforcement body can reach 15.6 MPa, and the 28d flexural strength can reach 2.3 MPa, showing good bonding and reinforcement ability for broken rock (as shown in the model Figure 1 ).

[0102] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A nanocarbon-reinforced ultra-fine cement-based barrier material, characterized in that, The raw material composition includes, by weight parts, cement 45-50, solid waste sintered active material 0.5-2.5, water reducing agent 0-0.05, carbon nanotube 0.015-0.1, carbon quantum dot 1% solution 0.5-2.5, and water 45-50; The solid waste sintered active material is building waste of sulphoaluminate cement; The building waste of sulphoaluminate cement is calcined solid waste sulphoaluminate processed by superfine grinding technology and air classification technology.

2. The nanocarbon-enhanced ultra-fine cement-based barrier material of claim 1, wherein, The raw material composition of the superfine cement-based blocking material includes, by weight parts, cement 49, solid waste sintered active material 1.0, water reducing agent 0.05, carbon nanotube 0.1, carbon quantum dot 1% solution 0.5, and water 49.

5.

3. The nanocarbon-enhanced ultra-fine cement-based barrier material according to any one of claims 1-2, wherein, The cement adopts K700 superfine cement, and the fineness D90 is 18.3 μm.

4. The nanocarbon-enhanced ultra-fine cement-based barrier material according to any one of claims 1 to 2, wherein The carbon nanotube is selected from one or more of single-walled carbon nanotube, multi-walled carbon nanotube, double-walled carbon nanotube, open carbon nanotube, and closed carbon nanotube.

5. The nanocarbon-enhanced ultra-fine cement-based barrier material according to any one of claims 1 to 2, wherein the nanocarbon is carbon nanotubes. The carbon quantum dot 1% solution is prepared with a solid carbon quantum dot to water volume ratio of 1:

100.

6. A method of producing a nanocarbon-reinforced ultra-fine cement-based barrier material according to any one of claims 1 to 5, characterized in that The method comprises the following steps: S1, mixing cement, solid waste sintered active material, and water reducing agent to obtain a powder component; S2, mixing carbon nanotube, carbon quantum dot 1% solution, and water to obtain a liquid component; S3, mixing the powder component and the liquid component to obtain the superfine cement-based blocking material.

7. The production method according to claim 6, wherein In step S1, the weight ratio of the cement, solid waste sintered active material, and water reducing agent is 45-50:0.5-2.5:0-0.05; the water reducing agent is polycarboxylic acid superplasticizer powder.

8. The production method according to claim 6, wherein In step S2, the carbon nanotube is fully dispersed in the mixed solution before mixing the powder component.

9. Application of the nano-carbon enhanced superfine cement-based blocking material of any one of claims 1-5 in the control and prevention of mine groundwater pollution.

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